The Form Of Cavitation Cloud And Its Effect On Atomization Performance In Self-excited Oscillation Pulsed Atomizing Nozzle

The cavitation inside the nozzle has an important effect on enhancing the atomization effect of the jet.The self-excited oscillation pulsed atomizing nozzle can make the jet cavitation effect due to its special geometry,which can effectively improve the spray performance of the jet.Therefore,the study of its spray characteristics is great significance to the development of jet spray technology.In this paper,the influence of the transient structure in the nozzle on the spray performance of the nozzle is analyzed by studying the transient flow structure inside the nozzle and its evolution.Based on the flow field inside and outside the joint nozzle,the spray performance of self-excited oscillation pulsed atomizing nozzle was investigated.The main research content is:(1)Based on the advantages and disadvantages and application characteristics and application scope of the turbulence model and multiphase flow model and cavitation model in the finite element analysis,the coupled LES/Mixture/Schnerr-Saurer calculation method was proposed to calculate the transient flow of gas-liquid two-phase flow in a self-excited oscillation pulsed atomizing nozzle.And by comparing the test results to verify the accuracy of the proposed mathematical model.(2)The established LES/Mixture/Schnerr-Saurer mathematical model was used to investigate the instantaneous flow form of the cavitation cloud in a self-excited oscillation pulsed atomizing nozzle.The evolution of cavitation clouds in an oscillation cycle and the effect of different Reynolds numbers on the volume fraction of cavitation clouds are analyzed.And the effects of different forms of cavitation clouds on the nozzle spray performance are analyzed.(3)Established the Euler-Lagrange spray model for the flow field inside and outside the nozzle.The influence of cavitation bubble collapse and pulse effects on the spray characteristics of nozzles were investigated by comparing the spray patterns of self-excited oscillation pulsed atomizing nozzle and conventional nozzles.By analyzing the influence of different structural parameters on the average diameter of Sutter,the spray angle and the spray penetration,the influence law of structural parameters on the atomization performance,and the range of nozzle structural parameters with good spray effect were obtained.